1. Field of the Invention
The present invention relates to a cigarette filter-manufacturing apparatus to be incorporated in equipment for manufacturing filter-tipped cigarettes, and more particularly to a cigarette filter-manufacturing apparatus capable of producing cigarette filters of various sizes.
2. Description of the Related Art
A cigarette filter-manufacturing apparatus of this type comprises a hopper for storing a large number of filter rods having a predetermined length. The filter rods are supplied one by one from the hopper to a cutting drum. This cutting drum has a number of filter rod-transporting grooves formed in the circumference thereof at regular intervals, and the transporting grooves has a size suitable for receiving the filter rods. A filter rod supplied from the hopper are received in a transporting groove of the cutting drum, and is transported as the cutting drum rotates.
One or more one annular slits are formed in the circumference of the cutting drum such that they extend across the filter rod-transporting grooves. The annular slits are located at such positions that the filter rod in each transporting groove can be divided in equal parts. One or more circular cutting blades, the number of which is equal to that of annular slits, are arranged in the vicinity of the circumference of the cutting drum. Each cutting blade has its edge located in the corresponding annular slit. The filter rod received in a filter rod-transporting groove is transported with the rotation of the cutting drum and is cut or divided in equal parts when it passes the cutting blades. In this manner, filter plugs, each of which is twice as long as a cigarette filter, are obtained.
The filter plugs, obtained by cutting the filter rod on the cutting drum, are received and carried by a succeeding grooved drum. While they are carried, they are arranged such that their lengthwise directions are perpendicular to the direction in which they are carried. Thereafter, they are supplied to a wrapping machine, which is part of the filter-tipped cigarette manufacturing equipment.
Hitherto, filter-tipped cigarettes of various brand names have been on sale. Since the variety of brand names results from using different kinds of tobacco leaves, changing the mixing rate thereof, or diversifying the packet design, it is expected that filter-tipped cigarettes of new brand names will be on sale in the future by varying the length of cigarette filters.
In order to vary the length of cigarette filters or filter plugs by use of the above-mentioned cigarette filter-manufacturing apparatus, the cutting drum must be replaced with another, and the positions of cutting blades must be adjusted accordingly since the edges of the cutting blades are located within the annular slits of the cutting drum. The replacement of the cutting drum is necessary since the positions of the annular slits have to be changed in accordance with the length of the filter plugs to be manufactured. If the positions of the annular slits are changed, the positions of the cutting blades have to be changed accordingly. Therefore, the replacement of the cutting drum and the adjustment of the positions of the cutting blades are laborious and time-consuming.
A filter rod-manufacturing apparatus presently available is designed to produce filter rods of a prescribed length, e.g., 120 mm. Therefore, if filter plugs shorter than 20 mm are required, a 120 mm-filter rod has to be cut into six equal parts. Conversely, if filter plugs longer than 20 mm are required, the 120 mm-filter rod is usually cut into four equal parts. To cope with these requirements, the above-mentioned replacement of the cutting drum is necessary, and further the cutting blades have to be adjusted in position after determining the appropriate number of cutting blades to be employed. In addition, the filter plug-transporting drums succeeding to the cutting drum have to be modified, as well as their driving mechanisms.